Systems for sub-ambient pressure assisted actuation of subsea hydraulically actuated devices and related methods

ABSTRACT

This disclosure includes systems and methods for actuation of subsea hydraulically actuated devices. Some systems use or include one or more subsea reservoirs, each having a body defining an interior volume configured to contain a sub-ambient internal pressure, the body defining an outlet in fluid communication with the interior volume, and a hydraulic power delivery system including one or more subsea valves configured to selectively allow fluid communication between the outlet of at least one of the reservoir(s) and a first port of the hydraulically actuated device. In some systems, the hydraulic power delivery system includes a rigid sliding member configured to unseal a selectively sealed outlet of at least one of the reservoir(s). In some systems, the subsea valve(s) are configured to alternatively allow fluid communication between the outlet of the at least one of the reservoir(s) and the first or a second port of the hydraulically actuated device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.61/973,782, entitled “SYSTEMS AND METHODS FOR LOW-PRESSURE ACTUATION OFSUBSEA HYDRAULIC RAMS,” filed Apr. 1, 2014, the content of which isincorporated by reference in its entirety.

BACKGROUND

1. Field of Invention

The present invention relates generally to subsea blowout preventers,and more specifically, but not by way of limitation, to systems andmethods for sub-ambient pressure assisted actuation of subseahydraulically actuated devices.

2. Description of Related Art

A blowout preventer (BOP) is a mechanical device, usually installedredundantly in stacks, used to seal, control, and/or monitor oil and gaswells. Typically, a blowout preventer includes a number of devices, suchas, for example, rams, annulars, accumulators, test valves, failsafevalves, kill and/or choke lines and/or valves, riser joints, hydraulicconnectors, and/or the like, many of which may be hydraulicallyactuated.

Such hydraulically actuated devices (amongst others) typically requiresources of high pressure for actuation. In subsea applications, andparticularly those in which the subsea environment is used as a pressuresink, pressure requirements for such sources of high pressure generallyincrease with depth below the sea surface.

Examples of sub-ambient pressure assisted actuation of subseahydraulically actuated devices are disclosed in: (1) U.S. Pat. No.8,387,706; and (2) U.S. Pat. No. 8,602,109.

SUMMARY

Some embodiments of the present systems are configured to allow forsub-ambient pressure assisted actuation of two or more functions of asubsea hydraulically actuated device (e.g., an open function and a closefunction of a ram-type BOP) (e.g., through one or more subsea valvesconfigured to alternatively allow fluid communication between one ormore pressure sinks at sub-ambient pressures and: (1) a first port ofthe hydraulically actuated device; or (2) a second port of thehydraulically actuated device). Some embodiments of the present systemsare configured, through one or more sealed reservoirs, each configuredto contain a sub-ambient internal pressure, and a rigid sliding memberconfigured to unseal at least one of the one or more reservoirs, toprevent internal pressure(s) of the one or more reservoirs fromequalizing with other system pressures prior to use, reduce the risk ofleakage from and/or into the one or more reservoirs prior to use,facilitate replacement of at least one of the one or more reservoirs,and/or the like.

Some embodiments of the present systems for actuating a subseahydraulically actuated device comprise: one or more subsea reservoirs,each comprising a body defining an interior volume configured to containan internal pressure that is lower than a pressure of a subseaenvironment outside of the body, the body defining an outlet in fluidcommunication with the interior volume, and a hydraulic power deliverysystem comprising one or more subsea valves, where the one or moresubsea valves are configured to selectively allow fluid communicationbetween the outlet of at least one of the one or more reservoirs and afirst port of the hydraulically actuated device. In some embodiments,the one or more subsea valves are configured to alternatively allowfluid communication between the outlet of at least one of the one ormore reservoirs and a first port of the hydraulically actuated device ora second port of the hydraulically actuated device.

In some embodiments, the outlet of at least one of the one or moresubsea reservoirs is selective sealed, and the hydraulic power deliverysystem comprises a rigid sliding member (e.g., a ram, rod, penetrator,and/or the like) configured to unseal the outlet of at least one of theone or more reservoirs. In some embodiments, the outlet of at least oneof the one or more reservoirs comprises a diaphragm, and the rigidsliding member is configured to puncture the diaphragm to unseal theoutlet of at least one of the one or more reservoirs. In someembodiments, the rigid sliding member comprises a ram slidably disposedwithin a bore and movable between a first position and a secondposition, the ram configured to puncture the diaphragm of at least oneof the one or more reservoirs as the ram is moved between the firstposition and the second position, where fluid communication between thebore and the outlet is permitted when the ram is in the second position.

In some embodiments, the one or more subsea valves are configured toselectively allow fluid communication between a pressure source and thefirst port of the hydraulically actuated device. In some embodiments,the one or more subsea valves comprises a first three-way valveconfigured to selectively allow fluid communication between the pressuresource and the first port of the hydraulically actuated device andselectively allow fluid communication between the outlet of at least oneof the one or more reservoirs and the first port of the hydraulicallyactuated device. In some embodiments, the one or more subsea valvescomprises a first two-way valve configured to selectively allow fluidcommunication between the pressure source and the first port of thehydraulically actuated device and a second two-way valve configured toselectively allow fluid communication between the outlet of at least oneof the one or more reservoirs and the first port of the hydraulicallyactuated device.

In some embodiments, the one or more subsea valves are configured toselectively allow fluid communication between a pressure source and thesecond port of the hydraulically actuated device. In some embodiments,the one or more subsea valves comprises a second three-way valveconfigured to selectively allow fluid communication between the pressuresource and the second port of the hydraulically actuated device andselectively allow fluid communication between the outlet of at least oneof the one or more reservoirs and the second port of the hydraulicallyactuated device. In some embodiments, the one or more subsea valvescomprises a third two-way valve configured to selectively allow fluidcommunication between the pressure source and the second port of thehydraulically actuated device and a fourth two-way valve configured toselectively allow fluid communication between the outlet of at least oneof the one or more reservoirs and the second port of the hydraulicallyactuated device.

In some embodiments, the pressure source comprises sea water from asubsea environment. In some embodiments, the pressure source comprises asubsea pump. In some embodiments, the pressure source comprises ahydraulic power unit.

In some embodiments, at least one of the one or more reservoirscomprises an accumulator. In some embodiments, the accumulator comprisesa piston-type accumulator. In some embodiments, the accumulatorcomprises a bladder-type accumulator. In some embodiments, at least oneof the one or more reservoirs is pressure-compensated. In someembodiments, the one or more reservoirs comprises two or morereservoirs. In some embodiments, the one or more reservoirs are coupledto a BOP stack. In some embodiments, at least one of the one or morereservoirs is configured to be retrievable by a remotely-operatedunderwater vehicle (ROV).

In some embodiments, at least one of the one or more subsea valvescomprises a hydraulically piloted subsea valve. In some embodiments, atleast one of the one or more subsea valves comprises an electrohydraulicservo valve. In some embodiments, the one or more subsea valves arecoupled to a manifold.

In some embodiments, the hydraulically actuated device comprises a BOP,the first port comprises an open port, and the second port comprises aclose port. Some embodiments comprise a battery configured to supplyelectrical power to the hydraulic power delivery system. Someembodiments comprise one or more sensors configured to capture dataindicative of at least one of pressure, flow rate, and temperature ofhydraulic fluid within the hydraulic power delivery system.

Some embodiments of the present methods for actuating a subseahydraulically actuated device comprise: unsealing a sealed outlet of asubsea reservoir, the reservoir defining an interior volume in fluidcommunication with the outlet, the interior volume containing aninternal pressure that is lower than a pressure of a subsea environmentoutside of the reservoir, and placing the outlet of the reservoir intofluid communication with a first port of the hydraulically actuateddevice. In some embodiments, unsealing the sealed outlet of thereservoir comprises puncturing a seal of the reservoir. Some embodimentscomprise placing a second port of the hydraulically actuated device intofluid communication with a pressure source.

Some embodiments of the present methods for actuating a subseahydraulically actuated device comprise: selecting a first port from atleast two ports of the hydraulically actuated device and placing theselected first port into fluid communication with an interior volume ofa subsea reservoir, the interior volume containing an internal pressurethat is lower than a pressure of a subsea environment outside of thereservoir. Some embodiments comprise placing a second port of the atleast two ports of the hydraulically actuated device into fluidcommunication with a pressure source. Some embodiments compriseselecting a second port from the at least two ports of the hydraulicallyactuated device and placing the selected second port into fluidcommunication with the interior volume of the subsea reservoir. Someembodiments comprise placing the selected first port into fluidcommunication with a pressure source.

The term “coupled” is defined as connected, although not necessarilydirectly, and not necessarily mechanically; two items that are “coupled”may be unitary with each other. The terms “a” and “an” are defined asone or more unless this disclosure explicitly requires otherwise. Theterm “substantially” is defined as largely but not necessarily whollywhat is specified (and includes what is specified; e.g., substantially90 degrees includes 90 degrees and substantially parallel includesparallel), as understood by a person of ordinary skill in the art. Inany disclosed embodiment, the term “substantially” may be substitutedwith “within [a percentage] of” what is specified, where the percentageincludes 0.1, 1, 5, and 10 percent.

Further, a device or system that is configured in a certain way isconfigured in at least that way, but it can also be configured in otherways than those specifically described.

The terms “comprise” (and any form of comprise, such as “comprises” and“comprising”), “have” (and any form of have, such as “has” and“having”), “include” (and any form of include, such as “includes” and“including”), and “contain” (and any form of contain, such as “contains”and “containing”) are open-ended linking verbs. As a result, anapparatus that “comprises,” “has,” “includes,” or “contains” one or moreelements possesses those one or more elements, but is not limited topossessing only those elements. Likewise, a method that “comprises,”“has,” “includes,” or “contains” one or more steps possesses those oneor more steps, but is not limited to possessing only those one or moresteps.

Any embodiment of any of the apparatuses, systems, and methods canconsist of or consist essentially of—rather thancomprise/include/contain/have—any of the described steps, elements,and/or features. Thus, in any of the claims, the term “consisting of” or“consisting essentially of” can be substituted for any of the open-endedlinking verbs recited above, in order to change the scope of a givenclaim from what it would otherwise be using the open-ended linking verb.

The feature or features of one embodiment may be applied to otherembodiments, even though not described or illustrated, unless expresslyprohibited by this disclosure or the nature of the embodiments.

Some details associated with the embodiments are described above andothers are described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings illustrate by way of example and not limitation.For the sake of brevity and clarity, every feature of a given structureis not always labeled in every figure in which that structure appears.Identical reference numbers do not necessarily indicate an identicalstructure. Rather, the same reference number may be used to indicate asimilar feature or a feature with similar functionality, as maynon-identical reference numbers. Views in the figures are drawn to scale(unless otherwise noted), meaning the sizes of the elements depicted ina view are accurate relative to each other for at least the embodimentdepicted in the view.

FIG. 1 is a diagram of a first embodiment of the present systems foractuating a subsea hydraulically actuated device.

FIG. 2 is a diagram of a second embodiment of the present systems foractuating a subsea hydraulically actuated device.

FIG. 3 is a diagram of a third embodiment of the present systems foractuating a subsea hydraulically actuated device.

FIGS. 4A and 4B are perspective and cross-sectional perspective views,respectively, of a reservoir, which may be suitable for use in someembodiments of the present systems.

FIG. 5 is a diagram of a reservoir bank, which may be suitable for usein some embodiments of the present systems.

FIG. 6A is a cross-sectional side view of an accumulator, which may besuitable for use in some embodiments of the present systems.

FIG. 6B is a cross-sectional side view of an accumulator, which may besuitable for use in some embodiments of the present systems.

FIG. 7 is a perspective view of an opening mechanism, which may besuitable for use in some embodiments of the present systems.

FIG. 8A is a cross-sectional side view of the opening mechanism of FIG.7, shown with a rigid sliding member in a first position.

FIG. 8B is a cross-sectional side view of the opening mechanism of FIG.7, shown with a rigid sliding member in a second position.

FIG. 8C is a cross-sectional perspective view of the opening mechanismof FIG. 8A.

FIG. 8D is a cross-sectional perspective view of the opening mechanismof FIG. 8B.

FIG. 9 is a perspective view of a ram, which may be suitable for use asa rigid sliding member in some embodiments of the present openingmechanisms.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring now to the drawings, and more particularly to FIG. 1, showntherein and designated by the reference numeral 10 a is a firstembodiment of the present systems. In the embodiment shown, system 10 ais configured for actuating a subsea hydraulically actuated device 14.The present systems can be configured to actuate any suitablehydraulically actuated device(s) (e.g., 14), such as, for example,ram(s), annular(s), accumulator(s), test valve(s), failsafe valve(s),kill and/or choke line(s) and/or valve(s), riser joint(s), hydraulicconnector(s), and/or the like. Such hydraulically actuated devices(e.g., 14) may include ports through which pressure (e.g., pressurizedfluid) may be conveyed to actuate one or more functions of thehydraulically actuated devices. For example, in this embodiment,hydraulically actuated device 14 comprises a ram-type BOP (onlypartially depicted), having a first port 18 (e.g., a ram-close port) anda second port 22 (e.g., a ram open port). In the depicted embodiment,hydraulically actuated device 14 comprises a first chamber 26 (e.g., aram-close chamber) in fluid communication with first port 18 and asecond chamber 30 (e.g., a ram-open chamber) in fluid communication withsecond port 22, where a piston 34 separates and is in fluidcommunication with each of the first and second chambers. To illustrate,in the embodiment shown, as a pressure within first chamber 26 isincreased and/or as a pressure within second chamber 30 is reduced,differences of internal pressures between the first chamber and thesecond chamber may cause piston 34 to move such that hydraulicallyactuated device 14 may actuate or begin to actuate a first function(e.g., a ram-close function). To further illustrate, in this embodiment,as a pressure within second chamber 30 is increased and/or as a pressurewithin first chamber 26 is reduced, differences of internal pressuresbetween the first chamber and the second chamber may cause piston 34 tomove such that hydraulically actuated device 14 may actuate or begin toactuate a second function (e.g., a ram-open function).

In the depicted embodiment, system 10 a comprises a hydraulic powerdelivery system 38 a. In this embodiment, hydraulic power deliverysystem 38 a is configured to allow fluid communication between one ormore ports (e.g., 18, 22) of one or more hydraulically actuated devices(e.g., 14) and one or more pressure sources (e.g., sources at a higherpressure than one or more pressure sinks) and/or one or more pressuresinks (e.g., sources at sub-ambient pressures, or pressures lower than apressure of a subsea environment, for example, a subsea environment inwhich one or more reservoirs 46 are disposed) to cause actuation of theone or more hydraulically actuated devices. In these ways and others,pressure requirements for a given pressure source to effectively actuatea hydraulically actuated device may be reduced, a pressure differential(e.g., between one or more pressure sources and one or more pressuresinks) available to actuate a hydraulically actuated device may beincreased, and/or the like.

As will be described in more detail below, such fluid communication maybe controlled via operation of one or more subsea valves (e.g., 58 a, 58b, and/or the like), ones of which (e.g., up to and including each ofwhich) may be coupled to (e.g., at least partially disposed within) amanifold 62 a. Subsea valves of the present systems may comprise anysuitable valve, such as, for example a spool valve, poppet valve, ballvalve, electrohydraulic servo valve, and/or the like, in any suitableconfiguration, such as, for example, two-position two-way (2P2W), 2P3W,2P4W, 3P4W, and/or the like, and may or may not be piloted (e.g.,hydraulically, electrically, mechanically, and/or the like).

Provided by way of example, in the embodiment shown, hydraulic powerdelivery system 38 a is configured to allow fluid communication betweenone or more ports (e.g., 18 and/or 22) of hydraulically actuated device14 and a subsea environment 42 a (e.g., a pressure source) and/or one ormore subsea reservoirs 46 (e.g., which may be configured as a pressuresink, described in more detail below). In embodiments configured to usesubsea environment 42 a as a pressure source (e.g., 10 a), one or moreshuttle valves (e.g., 50) may be used to mitigated undesired hydraulicfluid loss to the subsea environment and/or one or more filters (e.g.,54) may be used to mitigate the introduction of contaminants from thesubsea environment into a respective hydraulic power delivery system(e.g., 38 a). However, the present systems (e.g., 10 a, 10 b, 10 c,and/or the like) and/or respective hydraulic power delivery systems(e.g., 38 a, 38 b, 38 c, and/or the like) may be used with any suitablepressure source(s) (e.g., subsea environment 42 a, subsea pump(s) 42 b,hydraulic power unit(s) 42 c, which may be in fluid communication withthe respective hydraulic power delivery systems via hot line(s), rigidconduit(s), and/or the like) and/or any suitable pressure sink(s) (e.g.,one or more above sea reservoirs, one or more subsea reservoirs (e.g.,46), subsea pump(s), hydraulic power unit(s), and/or the like).

As mentioned above, in this embodiment, hydraulic power delivery system38 a comprises one or more subsea valves configured to selectively allowfluid communication between at least one of one or more reservoirs 46and a first port (e.g., 18) of hydraulically actuated device 14. Forexample, in the depicted embodiment, hydraulic power delivery system 38a comprises a first three-way valve 58 a configured to selectively allowfluid communication between at least one of one or more reservoirs 46and the first port (e.g., 18) of hydraulically actuated device 14. Inthe embodiment shown, one or more subsea valves are configured toselectively allow fluid communication between a pressure source and thefirst port (e.g., 18) of hydraulically actuated device 14. For example,in this embodiment, first three-way valve 58 a is configured toselectively allow fluid communication between subsea environment 42 aand the first port (e.g., 18) of hydraulically actuated device 14.

In the depicted embodiment, one or more subsea valves are configured toselectively allow fluid communication between at least one of one ormore reservoirs 46 and a second port (e.g., 22) of hydraulicallyactuated device 14. For example, in the embodiment shown, hydraulicpower delivery system 38 a comprises a second three-way valve 58 bconfigured to selectively allow fluid communication between at least oneof one or more reservoirs 46 and the second port (e.g., 22) ofhydraulically actuated device 14. In this embodiment, one or more subseavalves are configured to selectively allow fluid communication between apressure source and the second port (e.g., 22) of hydraulically actuateddevice 14. For example, in the depicted embodiment, second three-wayvalve 58 b is configured to selectively allow fluid communicationbetween subsea environment 42 a and the second port (e.g., 22) ofhydraulically actuated device 14. In some embodiments, one or morevalves may be configured such that fluid communication between apressure source (e.g., 42 a) and a respective first port (e.g., 18 or22) may cause fluid communication between a pressure sink (e.g., one ormore subsea reservoirs 46) and a respective second port (e.g., 18 or 22,but not the first port).

In the embodiment shown, one or more subsea valves are configured toalternatively allow fluid communication between at least one of one ormore reservoirs 46 and: (1) a first port (e.g., 18 or 22) ofhydraulically actuated device 14; or (2) a second port (e.g., 18 or 22,but not the first port) of the hydraulically actuated device. Forexample, in this embodiment, first three-way valve 58 a may be actuatedto allow fluid communication between at least one of one or morereservoirs 46 and first port 18, and second three-way valve 58 b may beactuated to block fluid communication between the at least one of theone or more reservoirs and second port 22. For further example, in thedepicted embodiment, second three-way valve 58 b may be actuated toallow fluid communication between at least one of one or more reservoirs46 and second port 22, and first three-way valve 58 a may be actuated toblock fluid communication between the at least one of the one or morereservoirs and first port 18.

In the embodiment shown, hydraulic power delivery system 38 a comprisesa subsea pump 66, which may be configured to recharge at least one ofone or more reservoirs 46 (e.g., by removing hydraulic fluid from withinthe at least one of the one or more reservoirs, for example, when the atleast one of the one or more reservoirs is at least partially filledwith hydraulic fluid after use as a pressure sink). In this embodiment,hydraulic power delivery system 38 a comprises one or more ROV stabs 70,which may be configured to allow ROV control of hydraulic power deliverysystem 38 a and/or components thereof, such as, for example, one or moresubsea valves (e.g., 58 a, 58 b, and/or the like).

Referring now to FIG. 2, shown therein and designated by the referencenumeral 10 b is a second embodiment of the present systems. In theembodiment shown, system 10 b, and more particularly, hydraulic powerdelivery system 38 b, is configured to provide pressure (e.g.,pressurized fluid) from multiple pressure sources to ports (e.g., 18,22) of hydraulically actuated device 14 (e.g., via operation of one ormore subsea valves, such as, for example, 58 c, 58 d, 74, and/or thelike, which may be coupled to a manifold 62 b, for example, at leastpartially disposed within the manifold). For example, in thisembodiment, one or more valves are configured to provide pressure (e.g.,pressurized fluid) from one or more subsea pumps 42 b (e.g., each ofwhich may comprise an independent pressure source) and/or a hydraulicpower unit 42 c to a first port (e.g., 18) of hydraulically actuateddevice 14. For further example, in the depicted embodiment, one or morevalves are configured to provide pressure (e.g., pressurized fluid) fromone or more subsea pumps 42 b (e.g., each of which may comprise anindependent pressure source) and/or a hydraulic power unit 42 c to asecond port (e.g., 22) of hydraulically actuated device 14. In theembodiment shown, hydraulic power delivery system 38 b comprises one ormore isolation valves 74, which may be configured to isolate one or morepressure sources (e.g., one or more subsea pumps 42 b, hydraulic powerunit 42 c, and/or the like) and/or one or more pressure sinks (e.g., oneor more tanks 46) from one another.

As with system 10 a, system 10 b comprises three-way valves, 58 c and 58d, each configured to selectively allow fluid communication between arespective pressure source and a respective port of hydraulicallyactuated device 14 and each configured to selectively allow fluidcommunication between a respective at least one of one or morereservoirs 46 and the respective port of the hydraulically actuateddevice. In this embodiment, three-way valves 58 c and 58 d are eachhydraulically piloted (e.g., as shown) (e.g., by electrically actuatedpilot valves, which may receive power from a battery 72, umbilicalcable, and/or the like).

Referring now to FIG. 3, shown therein and designated by the referencenumeral 10 c is a third embodiment of the present systems. System 10 ccomprises sets of two or more two-way valves, each set configured toperform a same or similar function as a three-way valve (e.g., three-wayvalves 58 a and/or 58 b of system 10 a, three-way valves 58 c and/or 58d of system 10 b, and/or the like). For example, in the embodimentshown, one or more subsea valves (e.g., 58 e, 58 f, 58 g, 58 h, 74,and/or the like) (e.g., which may be coupled to a manifold 62 c, forexample, at least partially disposed within the manifold) comprises afirst two-way valve 58 e configured to selectively allow fluidcommunication between a pressure source (e.g., one or more subsea pumps42 b) and a first port (e.g., 18) of hydraulically actuated device 14.In this embodiment, one or more subsea valves comprises a second two-wayvalve 58 f configured to selectively allow fluid communication betweenat least one of one or more reservoirs 46 and the first port (e.g., 18)of hydraulically actuated device 14. In the depicted embodiment, one ormore subsea valves comprises a third two-way valve 58 g configured toselectively allow fluid communication between a pressure source (e.g.,one or more subsea pumps 42 b) and a second port (e.g., 22) ofhydraulically actuated device 14. In the embodiment shown, one or moresubsea valves comprises a fourth two-way valve 58 h configured toselectively allow fluid communication between at least one of one ormore reservoirs 46 and the second port (e.g., 22) of the hydraulicallyactuated device.

As with system 10 a, in the embodiment shown, one or more subsea valvesare configured to alternatively allow fluid communication between atleast one of one or more reservoirs 46 and: (1) a first port (e.g., 18or 22) of hydraulically actuated device 14; or (2) a second port (e.g.,18 or 22, but not the first port) of the hydraulically actuated device.For example, in this embodiment, second two-way valve 58 f may beactuated to allow fluid communication between at least one of one ormore reservoirs 46 and first port 18, and fourth two-way valve 58 h maybe actuated to block fluid communication between the at least one of theone or more reservoirs and second port 22. For further example, in thedepicted embodiment, fourth two-way valve 58 h may be actuated to allowfluid communication between at least one of one or more reservoirs 46and second port 22, and second three-way valve 58 f may be actuated toblock fluid communication between the at least one of the one or morereservoirs and first port 18.

The use of two two-way valves (e.g., as opposed to a single three-wayvalve) may facilitate system 10 c, and more particularly, hydraulicpower delivery system 38 c, in reducing potential single points offailure. Thus, implementation of two two-way valves (e.g., as inhydraulic power delivery system 38 c) can increase reliability and faulttolerance over a single (e.g., three-way) valve configuration, despitepotentially requiring more components. Additionally, two-way valves aregenerally less expensive and less complicated than three-way valves andmay provide for a better seal and be more robust.

In this embodiment, system 10 c comprises one or more sensors 78configured to capture data indicative of at least one of hydraulic fluidpressure, temperature, flow rate, and/or the like. One or more sensors(e.g., 78) of the present systems can comprise any suitable sensor, suchas, for example, a temperature sensor (e.g., a thermocouple, resistancetemperature detector (RTDs), and/or the like), pressure sensor (e.g., apiezoelectric pressure sensor, strain gauges and/or the like), positionsensor (e.g., a Hall effect sensor, linear variable differentialtransformer, potentiometer, and/or the like), velocity sensor (e.g., anobservation-based sensor, accelerometer-based sensor, and/or the like),acceleration sensor, flow sensor, current sensor, and/or the like,whether external and/or internal to manifold 62 c, hydraulic powerdelivery system 38 c, and/or system 10 c, and whether virtual and/orphysical. Data captured by at least one of one or more sensors 78 may becommunicated to (e.g., an above-sea) controller, used, at least in part,to control system 10 c (e.g., one or more valves thereof), and/or thelike.

Referring additionally to FIGS. 4A and 4B, shown are perspective andcross-sectional perspective views, respectively, of a reservoir 46 a,which may be suitable for use in some embodiments of the present systems(e.g., 10 a, 10 b, 10 c, and/or the like) (e.g., as at least one of oneor more reservoirs 46). In the embodiment shown, reservoir 46 acomprises a body 82 defining an interior volume 86 configured to containand/or containing an internal pressure that is lower than a pressure ofa subsea environment outside of the body (e.g., a sub-ambient pressure).In this embodiment, body 82 defines an outlet 90 in fluid communicationwith interior volume 86. In the depicted embodiment, outlet 90 ofreservoir 46 a is selectively sealed. For example, in the embodimentshown, outlet 90 of reservoir 46 a is sealingly covered by a diaphragm94 (e.g., which may prevent fluid communication into and/or frominterior volume 86 through and/or out of outlet 90). Diaphragm 94 may becoupled to body 82 in any suitable fashion, such as, for example, viaintegral formation (e.g., such that the diaphragm is unitary with atleast a portion of the body), interlocking features of the diaphragmand/or body (e.g., a threaded coupling between the diaphragm and thebody), one or more fasteners, welding, and/or the like.

Referring additionally to FIG. 5, shown is a diagram of a reservoir bank98, which may be suitable for use in some embodiments of the presentsystems (e.g., 10 a, 10 b, 10 c, and/or the like). As shown, in thisembodiment, one or more reservoirs 46 comprises two or more reservoirs(e.g., five (5) reservoirs, as shown). In the depicted embodiment,reservoir bank 98 and/or one or more reservoirs 46 (e.g., whether or notthe one or more reservoirs are disposed in a reservoir bank) may becoupled to a BOP and/or BOP stack.

In some embodiments, respective reservoir banks (e.g., 98) and/or atleast one of respective one or more reservoirs (e.g., 46) may beconfigured to be ROV retrievable. For example, in the embodiment shown,reservoir bank 98 comprises one or more isolation valves 102, each influid communication with a respective one of one or more reservoirs 46.In this embodiment, at least one of one or more isolation valves 102 maybe actuated to block fluid communication to and/or from a respective atleast one of one or more reservoirs 46 (e.g., thus facilitating removalof the respective reservoir(s) from reservoir bank 98 and/or from system10 a, 10 b, 10 c, and/or the like).

In some embodiments, at least one of respective one or more reservoirs(e.g., 46) may comprise an accumulator. For example, FIG. 6A shows across-sectional side view of a (e.g., piston-type) accumulator 46 b,which may be suitable for use in some embodiments of the present systems(e.g., 10 a, 10 b, 10 c, and/or the like). In the embodiment shown,accumulator 46 b comprises a body 106 defining an interior volume 110.In this embodiment, accumulator 46 b comprises a piston 114 slidablydisposed within interior volume 110 and configured separate the interiorvolume into a first portion 118 and a second portion 122 (e.g., and thepiston may be biased towards the first portion or second portion via oneor more springs and/or the like).

In the depicted embodiment, first portion 118 is configured to containand/or contains an internal pressure that is lower than a pressure of asubsea environment outside of body 106 (e.g., a sub-ambient pressure).In the embodiment shown, second portion 122 is configured to receivehydraulic fluid (e.g., via outlet 90, which may be selectively sealed,similarly to as described above for reservoir 46 a). In this embodiment,when accumulator 46 b is placed in fluid communication with a port(e.g., 18 or 22) of a hydraulically actuated device (e.g., 14), aninternal pressure within second portion 122 may increase, causing piston114 to move towards first portion 118 (e.g., thus compressing a fluid,such as a gas, within the first portion). As shown, accumulator 46 bcomprises a valve 124 (e.g., to facilitate filling and/or re-filling offirst portion 118 with fluid at a sub-ambient pressure).

For further example, FIG. 6B shows a cross-sectional side view of a(e.g., bladder-type) accumulator 46 c, which may be suitable for use insome embodiments of the present systems (e.g., 10 a, 10 b, 10 c, and/orthe like). In the embodiment shown, accumulator 46 c comprises a body126 defining an interior volume 130 containing a flexible bladder 134(e.g., whether elastic and/or inelastic). In the depicted embodiment,flexible bladder 134 is disposed within body 126 such that a wall of theflexible bladder defines two portions of interior volume 130: a firstportion 138 within flexible bladder 134, and a second portion 142outside of the flexible bladder.

In the embodiment shown, first portion 138 is configured to containand/or contains an internal pressure that is lower than a pressure of asubsea environment outside of body 126 (e.g., a sub-ambient pressure).In this embodiment, second portion 142 is configured to receivehydraulic fluid (e.g., via outlet 90, which may be selectively sealed,similarly to as described above for reservoir 46 a). In the depictedembodiment, when accumulator 46 c is placed in fluid communication witha port (e.g., 18 and/or 22) of a hydraulically actuated device (e.g.,14), an internal pressure within second portion 142 may increase,causing portions of flexible bladder 134 to displace towards firstportion 138 (e.g., thus compressing a fluid, such as a gas, within theflexible bladder). As shown, accumulator 46 c comprises ananti-extrusion poppet valve 146 configured to prevent extrusion offlexible bladder 134 out of outlet 90.

Referring now to FIGS. 7 and 8A-8D, shown are various views of anopening mechanism 150, which may be suitable for use in some embodimentsof the present systems (e.g., 10 a, 10 b, 10 c, and/or the like), andmore particularly, in some embodiments of the present hydraulic powerdelivery systems (e.g., 38 a, 38 b, 38 c, and/or the like). In theembodiment shown, opening mechanism 150 comprises a body 154 defining afirst bore 158 and a second bore 162, the second bore configured to bein fluid communication with the first bore. In this embodiment, openingmechanism 150 is configured to be coupled to a respective one of one ormore reservoirs 46 (e.g., reservoir 46 a, as shown) such that first bore158 is in fluid communication with interior volume 86 of the respectivereservoir (e.g., when outlet 90 of the respective reservoir isunsealed). In the depicted embodiment, second bore 162 is configured toconnect opening mechanism 150 in fluid communication with othercomponents (e.g., at least one of one or more subsea valves 58, at leastone of one or more isolation valves 74, and/or the like) of the presentsystems.

In the depicted embodiment, opening mechanism 150 comprises a rigidsliding member 166. For example, in the embodiment shown, rigid slidingmember 166 is slidably disposed within first bore 158 and movablerelative to body 154 between a first position (FIGS. 8A, 8C) and asecond position (FIGS. 8B, 8D) (e.g., generally along a directionindicated by arrow 174); however, the rigid sliding member may bemovable beyond the first position and/or the second position. In thisembodiment, rigid sliding member 166 is sealingly, yet slidably, engagedwith first bore 158, for example, via one or more O-rings 170. Suchmovement of rigid sliding member 166 relative to body 154 between thefirst position and the second position may be accomplished in anysuitable fashion, such as, for example, via one or more hydraulic,electric, magnetic, and/or pneumatic actuators (e.g., screw-typeactuators, linear actuators, and/or the like), application of hydraulicpressure (e.g., to second end 188 of ram 178, described in more detailbelow), and/or the like.

In the depicted embodiment, rigid sliding member 166 is configured tounseal outlet 90 of reservoir 46 a. For example, in the embodimentshown, rigid sliding member 166 is configured to puncture diaphragm 94of reservoir 46 a as the rigid sliding member is moved between the firstposition and the second position (e.g., as shown). Thus, in thisembodiment, when rigid sliding member 166 is at and/or near the secondposition, fluid communication may be allowed between interior volume 86and first and second bores, 158 and 162, respectively.

Referring additionally to FIG. 9, shown is perspective view of ram 178,which may be suitable for use as a rigid sliding member in someembodiments of the present opening mechanisms (e.g., 150). In theembodiment shown, ram 178 comprises a body 182 having a first end 186defining a puncturing tip, surface, or edge 190 (e.g., configured topuncture, cut, and/or otherwise rupture diaphragm 94 of reservoir 46 a)and a second end 188.

In this embodiment, body 182 has dimensions that correspond to interiordimensions of first bore 158 such that ram 178 may be slidably disposedwithin the first bore. For example, in this embodiment, body 182 has amaximum transverse dimension 194 that corresponds to or substantiallyequals (e.g., is slightly smaller than) a maximum transverse dimension198 of first bore 158. In this embodiment, body 182 comprises asubstantially circular cross-section (e.g., which corresponds to across-section of first bore 158) (e.g., with the exceptions ofportion(s) of the body that define one or more grooves 206 and/or neckportion 210, described in more detail below). However, in otherembodiments, bodies (e.g., 182) of respective rams (e.g., 178) maycomprise portions having any suitable cross-section(s), such as, forexample, circular, elliptical, and/or otherwise roundedcross-section(s), triangular, rectangular, and/or otherwise polygonalcross-section(s), and/or the like. In embodiments where portions ofbodies (e.g., 182) of respective rams (e.g., 178) and correspondingportions of respective first bores (e.g., 158) have non-circularcross-sections, such non-circular cross-sections may inhibit axialrotation of the respective rams relative to the respective first bores.In the depicted embodiment, first end 186 of body 182 has a maximumradius 202 (e.g., a transverse distance measured from a center of thebody to an exterior surface of the body) that is substantially equal toone half of maximum transverse dimension 194 of the body. In at leastthis way, first end 186 of body 182 may facilitate proper alignment ofand/or mitigate binding between ram 178 and first bore 158 (e.g., as ram178 is moved between the first position and the second position).

In the embodiment shown, first end 186 of body 182 defines one or moregrooves 206, which may be configured to allow fluid communicationthrough first bore 158 and past first end 186. In this embodiment, eachof one or more grooves 206 is linear (e.g., each of the one or moregrooves is defined by faces that are substantially planar); however, inother embodiments at least one of one or more grooves (e.g., 206) of arespective ram (e.g., 178) may be non-linear, helical, and/or the like.In this embodiment, body 182 defines a neck portion 210 between firstend 186 and second end 188 (e.g., a portion of the body between thefirst end and the second end that has a reduced transverse dimensionrelative to maximum transverse dimension 194). In the depictedembodiment, neck portion 210 of body 182 may be configured to enhancefluid communication between interior volume 86 and first and secondbores, 158 and 162, respectively (e.g., when diaphragm 94 is puncturedby ram 178) (e.g., by increasing a flow volume defined between ram 178and body 182).

However, in some embodiments, at least one of respective one or morereservoirs (e.g., 46) may not be sealed (e.g., by a diaphragm 94), andan opening mechanism (e.g., 150) corresponding to the at least onereservoir may be omitted (e.g., and fluid communication with an interiorvolume 86 of the at least one reservoir may be controlled instead viaone or more valves, such as, for example, an isolation valve 102).

For example, some embodiments of the present methods for actuating asubsea hydraulically actuated device (e.g., 14) comprise unsealing asealed outlet (e.g., outlet 90, sealed by a diaphragm 94) of a subseareservoir (e.g., 46 a, accumulator 46 b, and/or accumulator 46 c), thereservoir defining an interior volume (e.g., 86, 110, and/or 130) influid communication with the outlet, the interior volume containing aninternal pressure that is lower than a pressure of a subsea environmentoutside of the reservoir, and placing the outlet of the reservoir intofluid communication with a first port (e.g., 18 or 22) of thehydraulically actuated device. In some methods, unsealing the sealedoutlet of the subsea reservoir comprises puncturing a seal (e.g.,diaphragm 94) of the reservoir. Some methods comprise placing a secondport (e.g., 18 or 22, but not the first port) of the hydraulicallyactuated device into fluid communication with a pressure source.

Some embodiments of the present methods for actuating a subseahydraulically actuated device (e.g., 14) comprise selecting a first port(e.g., 18 or 22) from at least two ports (e.g., 18 and 22) of thehydraulically actuated device and placing the selected first port intofluid communication with an interior volume (e.g., 86, 110, and/or 130)of a subsea reservoir (e.g., 46 a, accumulator 46 b, and/or accumulator46 c), the interior volume containing an internal pressure that is lowerthan a pressure of a subsea environment outside of the reservoir. Somemethods comprise placing a second port (e.g., 18 or 22, but not thefirst port) of the at least two ports of the hydraulically actuateddevice into fluid communication with a pressure source. Some methodscomprise selecting a second port (e.g., 18 or 22, but not the firstport) from the at least two ports of the hydraulically actuated deviceand placing the selected second port into fluid communication with theinterior volume of the subsea reservoir. Some methods comprise placingthe selected first port into fluid communication with a pressure source.

The above specification and examples provide a complete description ofthe structure and use of illustrative embodiments. Although certainembodiments have been described above with a certain degree ofparticularity, or with reference to one or more individual embodiments,those skilled in the art could make numerous alterations to thedisclosed embodiments without departing from the scope of thisinvention. As such, the various illustrative embodiments of the methodsand systems are not intended to be limited to the particular formsdisclosed. Rather, they include all modifications and alternativesfalling within the scope of the claims, and embodiments other than theone shown may include some or all of the features of the depictedembodiment. For example, elements may be omitted or combined as aunitary structure, and/or connections may be substituted. Further, whereappropriate, aspects of any of the examples described above may becombined with aspects of any of the other examples described to formfurther examples having comparable or different properties and/orfunctions, and addressing the same or different problems. Similarly, itwill be understood that the benefits and advantages described above mayrelate to one embodiment or may relate to several embodiments.

Alternative or Additional Descriptions of Illustrative Embodiments

The following alternative or additional descriptions of features of oneor more embodiments of the present disclosure may be used, in partand/or in whole and in addition to and/or lieu of, some of thedescriptions provided above.

Some embodiments of the present systems comprise: a bank ofaccumulators, wherein said bank of accumulators comprises at least twohydraulic accumulators fluidically connected together and wherein thepressure within the hydraulic accumulators is less than ambient subseapressure, at least one manifold valve, and at least one BOP ramfluidically connected to said bank of accumulators through the at leastone manifold valve, wherein the at least one manifold valve actuates toexpose the at least one BOP ram to ambient subsea pressure and open theconnection to the bank of accumulators.

Some embodiments comprise ram chambers with dual ports. Some embodimentscomprise two-way valves fluidically connected to each port. Someembodiments comprise hydraulically-piloted valves. In some embodiments,the hydraulically-piloted valves are solenoid-actuated. Some embodimentscomprise servo-electric actuated valves.

Some embodiments comprise bladder-type accumulators. Some embodimentscomprise piston-type accumulators. Some embodiments comprisepressure-compensated accumulators. Some embodiments comprisebarrier-less tanks. In some embodiments, the bank of accumulators isROV-retrievable. In some embodiments, the bank of accumulators ismounted directly to a LMRP/BOP stack. Some embodiments comprise multiplebanks of accumulators.

In some embodiments, the system is powered by an electrical powersource. In some embodiments, an electrical umbilical connects the systemto the electrical power source. Some embodiments comprise a battery forback-up power.

Some embodiments comprise at least one sensor. Some embodiments compriseat least one pressure transducer. Some embodiments comprise at least onethermocouple. Some embodiments comprise at least one position sensor.

The claims are not intended to include, and should not be interpreted toinclude, means-plus- or step-plus-function limitations, unless such alimitation is explicitly recited in a given claim using the phrase(s)“means for” or “step for,” respectively.

1. (canceled)
 2. A system for actuating a subsea hydraulically actuateddevice, the system comprising: one or more subsea reservoirs, eachcomprising: a body defining an interior volume configured to contain aninternal pressure that is lower than a pressure of a subsea environmentoutside of the body, the body defining an outlet in fluid communicationwith the interior volume; where the outlet is selectively sealed; and ahydraulic power delivery system comprising: a rigid sliding memberconfigured to unseal the outlet of at least one of the one or morereservoirs; and one or more subsea valves; where the one or more subseavalves are configured to selectively allow fluid communication betweenthe outlet of the at least one of the one or more reservoirs and a firstport of the hydraulically actuated device.
 3. The system of claim 2,where: the outlet of the at least one of the one or more reservoirscomprises a diaphragm; and the rigid sliding member is configured topuncture the diaphragm to unseal the outlet of the at least one of theone or more reservoirs.
 4. The system of claim 3, where the rigidsliding member comprises: a ram slidably disposed within a bore andmovable between a first position and a second position, the ramconfigured to puncture the diaphragm as the ram is moved between thefirst position and the second position; where fluid communicationbetween the bore and the outlet is permitted when the ram is in thesecond position.
 5. (canceled)
 6. A system for actuating a subseahydraulically actuated device, the system comprising: one or more subseareservoirs, each comprising a body defining an interior volumeconfigured to contain an internal pressure that is lower than a pressureof a subsea environment outside of the body, the body defining an outletin fluid communication with the interior volume; and a hydraulic powerdelivery system comprising: one or more subsea valves; where the one ormore subsea valves are configured to alternatively allow fluidcommunication between the outlet of at least one of the one or morereservoirs and a first port of the hydraulically actuated device or asecond port of the hydraulically actuated device.
 7. The system of claim6, where: the outlet of the at least one of the one or more reservoirsis selectively sealed; and the hydraulic power delivery system comprisesa rigid sliding member configured to unseal the outlet of the at leastone of the one or more reservoirs.
 8. The system of claim 7, where: theoutlet of the at least one of the one or more reservoirs comprises adiaphragm; and the rigid sliding member is configured to puncture thediaphragm to unseal the outlet of the at least one of the one or morereservoirs.
 9. The system of claim 8, where the rigid sliding membercomprises: a ram slidably disposed within a bore and movable between afirst position and a second position, the ram configured to puncture thediaphragm as the ram is moved between the first position and the secondposition; where fluid communication between the bore and the outlet ispermitted when the ram is in the second position.
 10. (canceled)
 11. Thesystem of claim 6, where the one or more subsea valves are configured toselectively allow fluid communication between a pressure source and thesecond port of the hydraulically actuated device.
 12. The system ofclaim 11, where the one or more subsea valves comprises: a third two-wayvalve configured to selectively allow fluid communication between thepressure source and the second port of the hydraulically actuateddevice; and a fourth two-way valve configured to selectively allow fluidcommunication between the outlet of the at least one of the one or morereservoirs and the second port of the hydraulically actuated device. 13.The system of claim 11, where the one or more subsea valves comprises asecond three-way valve configured to: selectively allow fluidcommunication between the pressure source and the second port of thehydraulically actuated device; and selectively allow fluid communicationbetween the outlet of the at least one of the one or more reservoirs andthe second port of the hydraulically actuated device.
 14. The system ofany of claim 6, where the one or more subsea valves are configured toselectively allow fluid communication between a pressure source and thefirst port of the hydraulically actuated device.
 15. The system of claim14, where the one or more subsea valves comprises: a first two-way valveconfigured to selectively allow fluid communication between the pressuresource and the first port of the hydraulically actuated device; and asecond two-way valve configured to selectively allow fluid communicationbetween the outlet of the at least one of the one or more reservoirs andthe first port of the hydraulically actuated device.
 16. The system ofclaim 14, where the one or more subsea valves comprises a firstthree-way valve configured to: selectively allow fluid communicationbetween the pressure source and the first port of the hydraulicallyactuated device; and selectively allow fluid communication between theoutlet of the at least one of the one or more reservoirs and the firstport of the hydraulically actuated device.
 17. The system of claim 14,where the pressure source comprises sea water from a subsea environment.18. The system of claim 14 where the pressure source comprises a subseapump.
 19. (canceled)
 20. The system of claim 6, where at least one ofthe one or more reservoirs comprises an accumulator. 21-28. (canceled)29. The system of claim 2, comprising a battery configured to supplyelectrical power to the hydraulic power delivery system.
 30. (canceled)31. A method for actuating a subsea hydraulically actuated device, themethod comprising: unsealing a sealed outlet of a subsea reservoir, thereservoir defining an interior volume in fluid communication with theoutlet, the interior volume containing an internal pressure that islower than a pressure of a subsea environment outside of the reservoir;and placing the outlet of the reservoir into fluid communication with afirst port of the hydraulically actuated device.
 32. The method of claim31, where unsealing the sealed outlet of the subsea reservoir comprisespuncturing a seal of the reservoir.
 33. The method of claim 31,comprising: placing a second port of the hydraulically actuated deviceinto fluid communication with a pressure source. 34-37. (canceled)